It is typical that an electronic throttle control for trucks include redundant control inputs. Examples are disclosed in commonly owned U.S. Pat. Nos. 5,321,980; 5,237,891; 5,133,225, and 4,976,166, the disclosures of which are incorporated herein by reference. The engine throttle is adapted to respond to a varying electronic input of one control sensor to generate an increasing/decreasing speed of the engine. The second input produces an “on/off” electronic signal and, for example, if in the “on” position indicates the idle position of the truck pedal and it will override the first signal as necessary to drop the engine speed back to idle. The reverse may also occur, i.e., where the varying signal indicates the idle position of the truck pedal and the “on/off” signal indicates that the pedal is depressed, in which case again the lower speed (e.g., idle) will be generated.
Traditionally, these sensors have relied on contacting switch and potentiometer based technology, which generally limits the operating lifetime and reliability. The common form of these sensors provides an output voltage that is proportional to the degree to which the throttle control is depressed (Analog Position Signal), and one or more switched outputs that are used to validate whether the throttle control is in an ‘idle’ state (Idle Validation Switch).
An object of the invention is to provide the safety features of the typical contact type throttle control signal generation but with non-contacting throttle control sensors, e.g., to achieve longer wear life without sacrificing throttle control reliability.